My opinion is FC was a great site 1 year ago, but in the past year there have been amazing improvements that made a great site even better.
Surveys: I very, very rarely have any trouble with a survey revoking credit. I think it happened once for me in 2013. The qualifier screener questions on the FC surveys are much shorter, so there's no longer any issue with going through 15 minutes only to be told you don't qualify. When I screen out it tends to happen right after the demographics, and not 20 pages in.
100% free offers: These come up from time to time. I keep an eye on the phone call ones myself because they're a fast and easy way to make $1 or $2.
Videos: These are awesome. I can remember in the past going through stretches where there would be no videos available, but it seems to me for the longest time there are always enough videos that I can make over my $0.05 if I don't feel like doing Tasks. Multivue has been pushing out a ton of the press release videos.
Tasks: I don't really do these a ton. I tend to visit FC first thing in the morning when I wake up, and I'm usually too groggy. I usually hit them up when it's getting close to cashout time. The Crowdflower staff has honestly been trying their best to make improvements and screen the tasks before they get pushed to production, so you'll see less incorrect Gold Standard questions than before... but there are still some zingers. I think FC tends to have more Tasks than some of the other affiliates, maybe because it's strictly US/Canada? I'm not sure, but in any event I think you'll see a lot of improvements.
Out of all the GPT sites I belong to, this has been in the consistent #1 position for me as far as money earned.